Hey !
Can`t speak for the other resorts as we didn't get the chance yet to visit them but in April we stayed 4 nights in Amanusa and we absolutely loved it. we also were somewhat reluctant about noise and were tempted to extend our stay in Kila with a few more nights but we are so so glad we didn't do so. There is indeed some construction going on. However, noise pollution is negligible (at least when we were there). There is of however some visual pollution from nearby hotel construction but it didn't affect the tranquil atmosphere in the resort whatsoever. Before construction like 15 years ago... this place must have been out of the world but in fact it still is.
I`m about to post my review on Amanusa one of the next days when I`ll find the time. We stayed in a pool suite which, absolutely recommendable all tough not essential as the beach club is amazing and we spend at least a few hours per day there and on top there is the massive resort pool.